Dielectric spectra of doped AgBr emulsion systems. Effect of Hg2+, I– and Br– ions
Abstract
The influence of doped Hg2+, I– and Br– ions on the dielectric spectra of octahedral AgBr emulsions has been studied. Br– causes Hg2+ to be substituted for Ag+ in the surface lattice of AgBr. The dielectric absorption peak of the AgBr emulsion shifts to lower frequency following doping with Hg2+ because the dielectric conductivity of the sample, σ2, decreases. When the Hg2+ content was 1.3 × 10–2 mol molAgBr–1 the dielectric absorption peak no longer continued to shift to lower frequency. In the case of doping with Hg2+ and I– simultaneously, when the dopant contents were ⩽ 1.0 × 10–2 I– and ⩽ 6.5 × 10–3 Hg2+ mol molAgBr–1, fmax increased; when the dopant contents were 1.4 × 10–2 I– and 9.1 × 10–3 Hg2+ mol molAgBr–1, fmax decreased. However, Δlogfmax in both cases is less than that for doping with Hg2+ or I– alone.